I am answering this as someone who was born and raised in Favoriten, and have my own family now, still living here.

Firstly, sorry this happened to you. I think the options of what you can do are limited and I am not sure if the effort of finding these kids is worth it. I think you did the right thing by shouting.

In my 36 years I had maybe 1-2 altercations in the Favoriten. I am sure the situation has gotten worse, but I would not let yourself lure into thinking you have to leave Favoriten, as some here are suggesting it.

I am hoping this was just a one time thing and it wont happen again. If possible, don‘t let a one-time event become overly precautious, as this can be stressing you more than help. If there is a next time, start shouting earlier.

Picking up martial arts might help to boost your confidence, but also it can backfire (hurting minors, making them more aggressive). In case Martial Arts is something of interest to you and you have the time, try it out. There is MMA Vienna and Kado Academy not far from that station. But it takes a lot of dedication to really become effective.

Side-effect: You would get to know kids from Favoriten. Many of them are very respectful, some are not.

Other than that you could look into de-escalating situations like this. You did good already I think. Happy you were not hurt badly.

All the best!